MPFL RECONSTRUCTION. This procedure is recommended for patients who have had multiple kneecap dislocations.

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1 MPFL RECONSTRUCTION This procedure is recommended for patients who have had multiple kneecap dislocations. The inherent stability of the kneecap has been compromised by tearing of the ligament that acts as a check rein on the inside aspect of the kneecap. It also means that the kneecap is being pulled over excessively, to the outside, due to the imbalance that now exists. (This is like a tightrope walker who has lost balance on one side and is constantly being pulled over to the other side, due to the excess weight on the latter side)

2 This procedure corrects some of the soft tissue imbalances that exist after patella (kneecap) dislocation, but you must be aware that there was probably an inherent problem with your kneecap system to start with. This means that there may be other factors that contribute to kneecap dislocation other than the ligament injury. Factors that may contribute to dislocations: - General laxity of joints double-jointedness - Bony architecture that may not confine the kneecap properly - A high-riding kneecap this means that the kneecap does not get confined by the bones until the knee has bent a significant way, making it more prone to dislocation before it is confined. - Excessive muscle pull from the outside this can occur when there is excessive outward rotation of the hip, knees (knockkneed), ankles (walking with toes pointing outwards) or flat feet. - Severe trauma a repeat episode of significant force, or a sudden twist of your knee. All of the above means that you could have been more or less predisposed to this condition, and that by reconstructing the ligament, the risk of dislocation may be lower but there is no guarantee that it will never happen again. We will only be correcting one aspect of the situation WHY IS IT APPROPRIATE TO CARRY OUT THIS PROCEDURE? Repetetive dislocations, or even partial dislocations produce a lot of pressure and force across the kneecap joint and therefore each time this happens, the joint surface is at risk of being damaged. You may already have some damage, and even loose fragments, which is why I always carry out an initial arthroscopy prior to the reconstruction. There is also a risk of damage to other structures within the knee, and these would need to be addressed if they have occurred.

3 WHAT DOES THE MPFL RECONSTRUCTION PROCEDURE ENTAIL? Once I am satisfied that I have addressed all the damage within the knee, I then harvest a hamstring tendon. This means that I take out one of your hamstrings as it attaches to the inside of your leg, just below the knee. This is done through an inch long cut, and a special device is tunneled under the skin, over the tendon. The tendon is then cut off at about 20cm up the thigh, and the tendon is pulled out through the small cut. That cut is then closed and the hamstring tendon is prepared for use as a graft. There is a very, very low risk of problems occurring at the harvest/donor site and most patients don t even miss the tendon that gets sacrificed. Through 2 small cuts, each measuring about 3cm, (red lines, figure 1), which varies slightly from person to person, the graft is looped and attached to the side of the kneecap, and then to the usual attachment site on the femur(thigh bone), where the original ligament attaches. The latter attachment is by means of a screw holds the soft tissue in the bone.

4 View looking along length of leg Side view

5 POST-OPERATIVE MANAGEMENT Patients usually come in on the day of surgery. The hospital stay is either I or 2 nights, depending on pain control, mobility etc. You will be on crutches for 4 weeks, where you can touch your foot down during this time, but nothing more than that. You will be walking with a bent knee, ie on tip-toes. Thereafter you can fully weight-bear. Range of movement can be achieved as soon as possible and the physios in the ward will guide you. Be prepared for a weakness of the thigh muscles for a few months, and for a few weeks you won t be able to lift your leg up in the air in a straight position. I will see you at the 1 week mark. We will discuss the operation and commence formal physiotherapy. If appropriate, please shave your leg as per the diagram. I hope this information has been helpful. Please make contact with me if you have any further queries.